H-guide type coupling for coaxial output



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Dec. 18, 1956 J. KLINE H-GUIDE TYPE COUPLING FOR COAXIAL. OUTPUT Filed Sept. 27, 1955 INVENTOR. JHCK KL/NE WOW x HTTOE/YEYJ United States Patent H-GUIDE TYPE COUPLING FOR COAXIAL OUTPUT Jack Kline, Concord, Mass., assignor to the United States of America as represented by the Secretary of the Air Force Application September 27, 1955, Serial No. 537,077

1 Claim. (Cl. 315-39) This invention relates to an H-guide type means to couple power from a magnetron to a coaxial output line.

The conventional loop coupling used to couple power from a magnetron -to a coaxial line is subject to many difficulties. Variation in coupling due to manufacturing tolerances is often so large in loop arrangements as to require separate adjustment for every mode in order to get repeatable loading. In vane type magnetrons having small vane to vane spacing the use of a loop introduces extremely small vane to loop spacing. The necessity of using a very small coaxial section may introduce loss and often introduces mechanical and production problems related to small tolerances.

It is an object of this invention to provide a magnetron power output coupling means which avoids the above noted difiiculties arising from loop coupling.

It is a further object of this invention to provide a magnetron coupling means which is mechanically simple and economical to produce, and is equally eflicient and more reliable than loop coupling.

These objects are achieved by coupling the magnetron cavity to a coaxial output cable by means of an H-type wave guide section as will be described more fully below. It is well known that coaxial output is more flexible and in many installations more desirable than an all waveguide output. The H-type waveguide coupling section of the present invention eliminates the disadvantages of the loop coupling formerly used with coaxial output while permitting the retention of the desirable properties of coaxial output.

These and other objects and advantages will be apparent to those skilled in the art from the following specification and drawing forming a part thereof wherein like reference characters refer to like parts throughout and in which:

Figure 1 is a sectional view taken on the line 11 of Figure 3 and showing a vane type magnetron having coaxial output.

Figure 2 is a vertical section taken on the line 2--2 of Figure 1.

Figure 3 is a vertical section taken on the line 3-3 of Figure 1.

Referring now to the drawings, there is shown a magnetron which may, for example, be a type QK326 having an anode and vanes 11 forming resonant cavities with- 2,774,912 Patented Dec. 18, 1956 'ice in the anode structure. The cathode is not shown in order to simplify the drawings. One of the resonant cavities opens into a slot 14 in a block 13. Block 13 is surrounded by an annular member 12 and the entire assembly is mounted in a recess of the outer surface of anode 10 to form the H-guide section as may best be seen in Figures 1 and 2. In Figure 2 it will be noted that the H is formed by slot 14 and the spaces between blocks 13 and annular member 12. Plate member 17 is used to secure the block assembly in place and to asymmetrically attach the coaxial cable thereto. The coaxial cable has an outer shield member 15 and an inner conductor 16. It is clear from the drawings, particularly Figure 1, that the H-guid'e excites asymmetrically the principal coaxial mode of the cable.

The coupling arrangement illustrated has numerous advantages. The variation in coupling which is due to manufacturing tolerances will be small in contrast to loop couplers which must often be adjusted for every mode in order to get repeatable loading. The H-guide coupling simplifies the problem of getting proper coupling without introducing very small loop to vane spacings. This is particularly important for anodes with many vanes where the vane to vane spacing is small.' This coupling eliminates the necessity of using .a very small coaxial section which may introduce loss and often introduces mechanical and production problems related to small tolerances. The mechanical problems in the H-guide coupling are simple and result in an economical structure of relatively high efficiency. An output coupling system of the type illustrated has given :a seventy percent circuit efficiency when used with a magnetron type QK236.

While a preferred embodiment of the invention has been described in detail for purposes of illustration, it is obvious that many modifications are possible within the spirit and scope of the invention.

WhatIclaim is:

A magnetron having an anode member and a plurality of resonant cavities formed Within said anode, an annular recess in the outer surface of said anode, a block member mounted within said recess, said block member having a central slot communicating with one of the resonant cavities within said anode structure, an annular ring member surrounding said block within said recess, said ring member and said slotted block forming an H-type Waveguide, a coaxial output cable, means to asymmetrically attach said coaxial cable to said H-type waveguide so as to asymmetrically excite the principal mode of said cable from said waveguide whereby power is coupled from said resonant cavity to said coaxial cable.

References Cited in the file of this patent UNITED STATES PATENTS 2,659,029 Clogston et al. Nov. 10, 1953 2,659,031 Bokhove Nov. 10, 1953 2,724,090 Moore Nov. 15, 1955 2,749,477 Verweel June 5, 1956 

